Carbon blacks modified with organosilicon compounds, method of their production and their use in rubber mixtures

Abstract

Carbon black is reacted with at least one organosilicon compound of the General Formula [R.sup.1.sub.n (RO).sub.3-n Si-(Alk).sub.m -(Ar).sub.p ]q [B](I) R.sup.1.sub.n (RO).sub.3-n Si-(Alkyl) (II) or R.sup.1.sub.n (RO).sub.3-n Si-(Alkenyl) (III), and any excess of said organosilicon compound is extracted with a solvent. The products are useful as active fillers in rubber mixtures, carbon black suspensions and plastic mixtures which can be cross-linked with sulfur or peroxide.

What is claimed is: 
     
       1. Carbon blacks which are chemically modified with at least one organosilicon compound selected from the group consisting of   [R.sup.1.sub.n (RO).sub.3-n Si-(Alk).sub.m -(Ar).sub.p ]q [B](I)       R.sup.1.sub.n (RO).sub.3-n Si-(Alkyl)                      (II)       R.sup.1.sub.n (RO).sub.3-n Si-(Alkenyl)                    (III)     in which   B represents --SCN, --SH, --Cl, --NH 2  (if q=1) or --Sx--(if q=2),   R and R 1 , which may be the same or different, represent an alkyl group containing 1 to 4 carbon atoms or the phenyl group,   q represents 1 or 2,   n represents 0, 1 or 2,   Alk represents a bivalent straight or branched hydrocarbon group containing 1 to 6 carbon atoms,   m represents 0 or 1,   Ar represents an arylene group containing 6 to 12 carbon atoms,   p represents 0 or 1 provided that p and n do not simultaneously signify 0,   x represents a number from 2 to 8,   Alkyl represents a monovalent straight or branched unsaturated hydrocarbon group containing 1 to 20 carbon atoms,   alkenyl represents a monovalent straight or branched unsaturated hydrocarbon group containing 2 to 20 carbon atoms,   and on the surface of which blacks 0.1 to 15 % by weight of one or more of the named organosilicon compounds are bonded in such a manner that they can not be extracted with organic solvents.   
     
     
       2. Modified carbon blacks as set forth in claim 1 which exist in powder form, pellet form or as a granulate. 
     
     
       3. A method of producing the modified carbon blacks set forth in claim 1 or claim 2 which comprises forming a homogeneous mixture of at least one said organosilicon compound and the carbon black, then subsequently reacting said at least one organosilicon compound for 1 to 60 min. at 50° to 160° C. and then extracting any of said at least one organosilicon compound which is not reacted with an organic solvent. 
     
     
       4. A method according to claim 3 including pelletizing powdered modified carbon black or converting it into a granulate. 
     
     
       5. A method as set forth in claim 3 in which all of said organosilicon compound is reacted with said carbon black and none is extracted. 
     
     
       6. A vulcanizable rubber mixture comprising a vulcanizable rubber and a modified carbon black as set forth in claim 1 or claim 2. 
     
     
       7. Carbon blacks according to claim 1, wherein Ae contains 6 carbon atoms, Alkyl contains 2 to 8 carbon atoms and alkenyl contains 2 to 8 carbon atoms.